ABSTRACT Over the next 20 years, cancer incidence and mortality are expected to rise at staggering rates worldwide, with much of the burden concentrated in low- and middle-income countries (LMICs). Despite widescale availability of antiretroviral therapy (ART) in LMICs, women living with HIV remain vulnerable to both AIDS- and non-AIDS defining cancers such as cervical and breast cancer. This is because screening coverage for breast and cervical cancer is low ? and access to timely diagnosis and treatment is limited. In South Africa, for example, fewer than one-third of HIV-infected women undergo breast and cervical cancer screening at the recommended intervals. Attrition between cancer screening and treatment is also substantial among HIV-infected women in under- resourced South African settings. We seek to eliminate disparities in breast and cervical cancer outcomes among HIV-infected women in South Africa. In this application, we propose an innovative implementation science project to close the gap between cancer control policy and cancer screening practices in this high-risk population. Specific Aim 1 will use a sequential mixed-methods design consisting of focus groups, a discrete choice experiment (DCE), and in-depth interviews to study multi-level drivers of cancer screening and determine women?s preferences for cancer screening services. We will enroll 80 HIV-infected women and 32 men in 14 focus groups (8 participants in each group), 600 HIV-infected women in the DCE, and conduct 24 in- depth interviews with key stakeholders. In Specific Aim 2, we will co-create a multi-level intervention package with patients, providers, and policy makers, applying Design Thinking principles to design the package and assess its acceptability. We anticipate that the package will include training, clinical tools, and user-focused interventions applied at various levels of the Social Ecological Model to address the barriers identified in Aim 1. We will explore acceptability of the intervention package through user pre-testing workshops conducted with 6 user groups: 2 groups of HIV-infected women, 2 of healthcare providers, and 2 of policy makers. This project will provide robust preliminary data to inform larger-scale implementation trials to (1) promote uptake of cancer screening among women living with HIV and (2) improve retention in care for women who screen positive. We will leverage longstanding partnerships and a strong research infrastructure in Johannesburg to implement the proposed work.